They remember the social worker who made it clear she was determined to stop "those lesbians" gaining permanent care of the child they had fostered for years.

They also recall being asked to explain how they could provide a nurturing home compared with traditional heterosexual couples.

And who could forget the judgmental psychologist, who assessed their capacity to raise children by asking about their sex life, or whether they attended gay and lesbian rallies, and which woman "played the man" in their relationship.

"She concluded that Sam played the man because she does the lawn mowing," Cocks says. "And this was a psychologist! It was extraordinary."

Despite the underlying bigotry they faced as they sought to obtain permanent care of their foster children, the Melbourne couple have since spent 15 years raising what Cocks describes as a "stock-standard middle class family": as loving and imperfect as the next.

Home is an eight-bedroom house on a tree-lined street in Alphington, with four siblings in permanent care and two biological children. The kids attend conservative private schools where diversity is accepted and embraced. And weekends are spent juggling extracurricular activities, from ballet and soccer, to swimming and birthday parties.

The only thing missing, Cocks admits, is the legal recognition and certainty that adoption could provide.

As the debate around same-sex marriage intensifies nationally, Tracey and Sam are one of the many couples who find themselves in a separate battle for equality: this time, over Victoria's adoption laws.

While other Australian jurisdictions legalised gay adoption years ago, Victoria's Adoption Act – which the Andrews government is set to overhaul – limits such rights to single people, or heterosexual couples who are married or in defacto relationships.

The result is an illogical situation where same-sex couples can become foster carers but can't adopt a child permanently – even if that child has been in their care for years.

Nor can a lesbian or a gay man formally adopt their partner's children from a previous relationship, or jointly adopt a niece or nephew whose parents had died, or even jointly adopt a child born through surrogacy or IVF. Many couples can get a parenting order for children in their care, but once that child turns 18 the order expires, leaving them without the stability of legal recognition.While it might sound trivial for some, the implications are significant. Without legal certainty, children in permanent care can not automatically inherit from their foster parents; parents in "blended families" could be refused the right to determine medical treatment in the event of an emergency involving a non-biological child; and parents would also face a bureaucratic maze applying for passports or trying to relocate without the permission of their birth parent or a court order.

And then there's the stigma that comes with being considered less than others, simply because you happen to be part of a different type of family.

"Most of the time we're just driving to soccer, or forgetting ballet shoes, or trying to be the best parents we can be," Cocks says. "It's hard to believe some people see us differently or will feel upset that we exist or that our family structure is like it is."

The good news for same-sex families is that the Andrews Labor government believes it's time for a shift. In the corridors of power at Spring Street, legislation has quietly been drafted to bring Victoria into line with NSW, Western Australia, Tasmania and the ACT, where adoption equality has been a reality for years.

The changes are expected later this year, giving same-sex couples the right to adopt children known to them (such as those in step-parent families or under permanent care, which make up the bulk of adoptions) and also the right to adopt unknown infants (which account for about 20 adoptions per year).

Some safeguards may be put in place, but the fundamental point is that discrimination between gay and heterosexual couples who want to adopt will no longer exist under the law.

Government insiders admit change is long overdue. Gay adoption was recommended in a 240-page review by the Victorian Law Reform Commission in 2007, but the then Brumby government lacked the political courage to take up the proposal.

The difference now is that community attitudes have changed, and so too has Daniel Andrews, a former Brumby minister who has recently cast himself as a rainbow warrior when it comes gay rights.

Since coming to office nine months ago, the 43-year-old Catholic father-of-three has not only become the first Victorian premier to lead Melbourne's Pride March, he's also become the first leader to create a dedicated "equality" portfolio within his cabinet, the first to appoint a sexuality and gender commissioner, and the first to make the removal of discrimination for lesbian, gay, bisexual, transgender and intersex (LGBTI) people a central plank of his first-term agenda.

Indeed, last week, when the Baird government banned NSW schools from screening Gayby Baby, a documentary about the lives of four children from same-sex families, Andrews took to Facebook to describe the move as "cruel rubbish". When it comes to adoption reform, the expectations are now pretty high.

The problem is, the government faces two significant hurdles: powerful religious groups and an unpredictable state parliament.The Australian Christian Lobby, for instance, has made it clear it wants religious exemptions that would give faith-based welfare agencies the right to refuse to place children in the care of same-sex couples.

What's more, the group says, parents should also have the right to nominate that only straight families can adopt their child, arguing it would be in the child's "best interest" to be raised by a mother and a father.

ACL Victorian director Dan Flynn urged the government to follow in the footsteps of NSW, where exemptions were granted as part of the adoption reforms that passed there in 2010. He argues that without legal protection to act in accordance with their faith, some adoption agencies could be forced to close.

"If gay adoption is realised, allowing a faith-based exemption will not have a real effect on the number of gay adoptions, but it will give proper recognition to religious freedom and strike the right balance," Flynn says.

The unanswered question is whether the Victorian Coalition agrees. Politics, after all, is a numbers game, and the Andrews government has only 14 out of 40 seats in the Senate-style upper house.

This means that in order to pass its bill, Labor will require either the support of the Coalition (which has 16 upper house seats) or the backing of the five Greens and at least two of the five crossbenchers.

Opposition leader Matthew Guy has previously revealed he personally supported same-sex adoption and would allow Liberal MPs a conscience vote when legislation is introduced, but has also told The Sunday Age he would be "comfortable" giving exemptions to faith-based agencies "provided there are still services to look after gay couples".

The government, however, appears to have taken a different view.

"We are approaching this issue on the basis that we are seeking to remove discrimination from the Adoption Act – at any level. So I'm not sure how instituting, as NSW have done, a 'lesser' form of discrimination … is a good outcome in the interest of the child," says Equality Minister Martin Foley.

"Genuine equality, particularly for LGBTI people, should not be something that's up for some kind of debate. It just should be an accepted institutional part of who we are."

It's the kind of sentiment that Gayby Baby director Maya Newell would no doubt welcome given the events of recent weeks.

As the child of two lesbians who shared their 30th anniversary this year, Newell recalls growing up in a world where her family structure was rarely represented in the media, and where being open about same-sex parenting was rare.

Gayby Baby was designed to buck the trend, giving the community an insight into four children growing up in same-sex households. The strength of the film is in its simplicity – a boy learning to read; a girl aspiring to be a singer; teens traversing adolescence more broadly – but also in the fact that it is one of the first documentaries to tell the story of same-sex parenting from the perspective of the child.

What Newell didn't expect, however, was the furore that erupted last week, when Sydney's Daily Telegraph published a front page story claiming that parents at her former school, Burwood Girls High in NSW, had complained about the documentary being scheduled during class hours.

The coverage forced the Baird government into damage control, but as Newell revealed to the audience at the film's launch in Melbourne last week, the consequences went much deeper than politics: some students who had never experienced negativity at school ended up going home in tears because someone had told them they're "not normal".

"We shouldn't have to prove we're the same to be equal," she says.

Pete and Matt – whose son Graham is one of the four children featured in the documentary – were also appalled to find their story suddenly becoming politicised in the national press.

The couple now live in Fiji, but were among the first to adopt when NSW changed its laws a few years after they started fostering Graham and his brother, Michael, now aged 13 and 15. Asked if adoption made any difference to their family, Pete (who did not want his surname used) told The Sunday Age: "The difference between fostering and adoption is nothing and it's everything.

"The day after, we still had to make lunches and send our kids to school, or get them to the dentist or make sure their hair is cut. That sense of parenting didn't change, but deep down, the sense of connectivity between the four of us changed forever."

Australian Bureau of Statistics figures suggest that 6300 children were living with two same-sex parents in Australia on the night of the 2011 census. However, these are conservative estimates, because they don't necessarily capture children with single same-sex parents, households whose parents may refuse to identify as same-sex attracted due to stigma, or children living in co-parented arrangements or across two households.

The Australian Institute of Family Studies also estimates that 11 per cent of Australian gay men and 33 per cent of lesbians have children, although it is hard to quantify how many families have formally adopted, let alone how many would want to.

Berry Street policy director Julian Pocock – whose agency has spent the past few years actively recruiting gay couples to become foster carers – reckons a "significant and growing number" of Victorian carers would jump at the opportunity if given the chance.

Arguably, so too would many step-parent families, families with surrogate children, and blended families. Others simply want the equal right to choose – a bit like the debate surrounding marriage equality.

Northcote couple Anna Viola and her partner Belle Austriaco​ say they would welcome the opportunity to adopt in order to provide legal stability for their children.

Viola has a five-year-old girl she conceived through donor insemination when she was single; while Austriaco has a six-year-old boy conceived by Austriaco's former partner. The pair have been since together Viola's biological daughter Lily was an infant, but Austriaco and Lily aren't officially bound under law – and that worries them.

"There would need to be a watertight will in place that runs the gamut of situations, like power of attorney. Or what about if I'm indisposed for some reason and Belle has to rush Lily to hospital – would she be legally allowed to make certain decisions about Lily's medical treatment?" Viola asks.

"What a relief, and how lovely and pleasant it would be, just to be a legal unit so the kids could grow up with that certainty."

Back in Alphington, Tracey Cocks shares the sentiment. It's been a long time since she's had to endure the homophobic questions of judgmental psychologists, but there's no doubt stigma remains.

"People will often ask my kids who the 'real mother' is and our kids will invariably say: 'both of them'," Cocks says. "The smarter kids will then usually ask: well which one gave birth to you? And of course, for kids in permanent care, that's a double whammy – because neither of us did – so they'll often just lie and say they're adopted."

Soon enough, that could well be true.

Same sex adoption

Western Australia: legal since 2002

ACT: legal since 2004

NSW: legal since 2010

Tasmania: legal since 2013

Victoria: bill expected to be introduced 2015

NT, South Australia, and Queensland: not legal (though Qld allows single gay people to adopt.

Why change?

* Legal certainty of the relationship between parent and child.

* So courts consider the children in a family to be siblings regardless of biological relationship with a child.

* Allow children to automatically inherit from their permanent care parents.

* Allow parents to apply for passports, relocate interstate or overseas with the child without needing to seek birth family permission or a court order

* Emotional security so children's legal relationship with their permanent carers doesn't finish when they turn 18.

* Removal of stigma.